Carbureter.



B. N. PIERCE.

CARBURETER.

APPLlCATlON FILED FEB. 19. 1915.

2 SHEETSSHEET 1- B. N. PIERCE.

CARBURETER.

APPLICATION men FEB-19. ms.

Patented Apr. 23, 1918.

III

2 SHEETSSHEET 2.

wiituaooao BURT NEULON' PIERCE, FLINT, MICHIGAN.

CARBURETER.

memes.

Specification of Letters Patent.

Patented Apr. 23, rare.

Application filed February 19, 1915. Serial No. 9,324.

To all whom it may concern:

Be it known that I, BURT NnULon PIERCE, a citizen of the United States,reslding at Flint, in the county of Gencsee and State of Michigan, haveinvented certain new and useful Improvements in (larbureters, of whichthe following is a specification, reference being had therein to theaccompanying drawing.

This invention relates to certain new and useful improvements incarbureters adapted to be used in connection with hydrocarbon enginesand the like; the object being to provide a carbureter with a main fuelsupply nozzle having a main air inlet surrounding the same and overwhich is arranged a- Venturi tube whichextends into a mixing chamber ofthe carbureter and in which a partial vacuum is created by the suctionof the engine in order to draw the fuel out of the main supply nozzle sothat the same will be thoroughly mixed with the incoming volume of air.

Another object of the invention is to provide a carburetor with anauxiliary air cham ber below the mixing chamber and separated Itherefrom by a floating suction-controlled valve, said auxiliary airchamber having a high speed jet or noZZle extending into the same andterminating adjacent the floating valve which is provided with aninitial free movement in order to allow the same to be raised by thesuction of the engine and having adjustable means for retarding themovement of said valve in proportion to the suction of the engine,whereby an additional charge of gasolene is proportionately supplied tothe main mixing chamber as the speed of the engine is increased.

Another object of my invention is to provide novel means for retardingthe opening movement of the floating suction valve comprising a pivotedfork arrangedin the path of travel of said valve, having means forexerting a resistance to the movement of said fork and means foradjusting the position of said fork in respect to the suction-controlledfloating valve whereby the same can be adjusted to a nicety in order toobtain the proper mixture when running on high speed.

' Another object of the invention is to provide a carbureter which isexceedingly simple and cheap'in construction and one 1n which the sameis formed of a plurality of castings so united that a very compact car,-

and the novel features thereof formed in the bottom of bureter is formedand one which can be readily assembled or taken apart in order to makethe necessary repairs.

. Other and further objects and advantages of the invention will behereinafter set forth defined by the appended claims.

In the drawings- Figure 1, is a perspective of my improved constructionof carbureter;

Fig. 2, is a longitudinal vertical section through the same, showing thefuel supply casing in elevation;

Fig. 3, 1s a perspective of the auxiliary air casing and floating valve;

Fig. 4, is a perspective of the float chamber closure and Venturi tubesupport;

Fig. 5, is a perspective of the pivoted fork and crank shaft showing oneform of means for retarding the oscillation of the crank shaft in orderto produce a resistance to the opening movement of the floating suctioncontrolled valve;

Fig. .6, is a detail section showing another form'of means for exertinga resistance to the opening movement of the suction-controlled valve;and

Fig. 7 is a detail view of the Venturi tube showing the annular grooveand the obliquely arranged intersecting groove in order tobprovide meansfor adjusting the Venturi tu e.

Like numerals of reference refer to like parts in the several figures ofthe drawings.

In carrying out my improved construction of carbureter, I employ a bowl1 forming a fuel and float chamber 2 provided with the usual fuel supplychamber 3 having a needle valve, not shown, mounted therein forcontrolling the supply of fuel, said valve being controlled by a ringfloat 4 carried by the long arm 5 of a crank 6, this being the ordinaryform of fuel control now employed in carbureters and forming no part ofmy invention.

' Mounted within the float and fuel chamber 2 is a central tubularmember 7 having an enlarged lower end 8 which is annularly re duced andis seated in a central opening the bowl as clearly shown in Fig. 2.

The upper end of the tubular member 7 is provided with an annular flange9 forming a closure for the bowl 1. The enlarged portion 8 of thetubular member 7 is provided no choker valve 20.

ranged between the ends of the air duct and with an integral cross bar10 having a transverse passage 11 formed therein, the outer ends ofwhich communicate with the bottom of the bowl and said passage isintersected by a vertical passage 11 formed in an integral plug 12 whichis provided with an enlarged threaded portion 13.

The top of the cross bar 10 is provided with a threaded recess in whichis secured a nozzle 14 having a passage communicating with the passage11 formed in the plug as clearly shown in Fig. 2, and provided with avalve seat for a needle valve 15 which is provided with a threadedportion 16 working in a correspondingly threaded portion of the plug 12.

The plug is provided with a reduced threaded portion 17 over which isarranged a stufiing box 18 through which the valve stem passes, saidvalve stem being pro-v vided with a cross bar at its end in Order toallow the same'to be readily manipulated in order to adjust the flow ofgasolene through.- the nozzle 14. Y

Arranged over the opening in the bottom of the bowl, which is closed bythe enlarged lower end of the tubular member 7, is an air duct-19 havingmeans at its outer end for connecting the same to a suitable source ofsupply and provided with a suitable A lead gasket 21 is arthe bottom ofthe bowl 1 and said air duct is secured in position upon the bottom ofthe bowl by a nut 22 working on the threaded portion 13 of the plug 12.

From the construction so far described. it will be seen that a main fuelsupply nozzle is provided in a centrally arranged tubular member havinga main air supply in order to allow the air to be thoroughly mixed withthe liquid fuel sucked from the main nozzle. Mounted within the tubularmember 7 is a Venturi tube 23 which is provided with an annular groovein which extends a set screw 24 passing'through the tubular member 7 forsecuring the Venturi tube in position therein, said/tube extendingupwardly beyond the upper end of thebowl, as clearly shown and for thepurpose, as will be hereinafter fully described.

Mounted on the annular flange 9 is a casing 25 forming an auxiliary airchamber 26 which is provided with oppositely disposed air inlet ports27; said casing being secured to the annular flange 9 of the tubularmember 7 by screws 28 as clearly shown in Fig.

.2. The casing is provided with oppositely disposed apertured lugs 29for the purpose hereinafter fully described.

Arranged within the auxiliary air chamber 26 is a high speed nozzle 30carried by a tube 31 extending downwardly through the flange 9 of thetubular member and terminating adjacent the enlarged portion 8 lllountedon the top of the casing 25 is a casing 35 which is provided with anannular depending flange '38 seated in an annular rabbet formed onthecasing 25 said casings being secured together by screws 37 extendingthrough the apertured lugs 29 into suitably threaded sockets formed inthe easing 25, as clearly shown in Fig. 2.

The casing 35 is provided with a mixing chamber 38 at its lower end intowhich the upper end of the Venturi tube extends. A throttle chamber 39is formed at the upper end of the casing and is provided with a pivotedwing throttle valve 40.

The casing 35 is provided with a heating chamber 41 surrounding thethrottle chamber and the upper portion of the mixing chamber 38, havingan exhaust inlet tube 42 and an outlet 43 to which is connected aflexible tube 44.

The exhaust inlet 42 is provided with a wing valve 44' carried by a stem45 extending outwardly through the wall thereof and is provided with acrank arm 46 to which is connected a rod 47 having a connection at itsfree end with a crank arm 48 mounted on the outer end of the stem 49 ofthe throttle valve 40 of substantially the same con struction as thatshown in my prior patent granted to me, July 16, 1912, #1932937; themovement of the crank arm 48 being regulated by a screw 50 mounted in alug 51 extending from the casing 35 in the path of travel of said crank.

The inner wall of the mixing chamber is provided with an apertured lug52 in which is mounted the inner end of a shaft 53, the outer endportion being mounted in a suitable bearing 54 formed on the casing 35as clearly shown in Fig. 1.

Mounted on the inner end of the shaft 53 adjacent the lug 52 is a fork55 which is secured in position thereon by a set screw 56, the arms ofSaid fork being provided with depending ends 57 arranged in the path oftravel of the floating valve 33 for the purpose of retarding the upwardmovement of tached.

naeaiae floating valve, the relative position of the arms to thefloating valve being adjusted by an arm 62 secured on the shaft 63 andprovided with an adjustingscrew 64 at its outer end which contacts witha suitable lug on the casing 35. By this construction, it will be seenthat the position of the arms of the fork can be readily adjusted inrespect to the floating valve and I have found by experimenting thatunder ordinary conditions, the arms are adjusted so that the valve isallowed. a slight vertical movement before the arms are engaged toexert-a resistance to the valve in its upward movement. By thisconstruction, it will be seen that as the speed of the engine isincreased, the suction .is increased to such an-extent-that the floatingvalve is raised upwardly against the resistance of the arms which arenormally held in lowered position by the weight, and. it will also beseen that by, adjusting the weight on the crank arm carried by the shaft53, the

resistance exerted against the floating valve can be readily increasedor decreased to suit the motor to which the carbureter is at- While Ihave shownin the preferred form, a weight for exerting a resistance tothe upper movement of the floating suction valve, it is, of'course,understood that any form of dash pot can be used for accon1- plishingthe same purpose and in Fig. 6,

the fuel bowl 65 is provided with an integral cylinder 66 having apassage 67 communicating with the lower end. Mounted within the cylinder66 is a piston 68 provided with a piston rod 69 having its upper endslidably connected to a crank arm 70 carried by the shaft 53, saidcylinder being closed at its upper end by a cap 71.

Arranged within the cylinder under the piston 68 is a coil spring 72 andit will be seen that by a construction as shown in this form, when theshaft 53 is oscillated by the upward movement of the suction-controlledfloating valve, a resistance is exerted against the upward movement onthe downward movement of the piston within the cylinder and while I haveshown a spring for increasing the resistance of the downward move mentof the piston it is, of course, understood that this can be dispensedwith and that the liquid can be relied upon to form the resistance.

While I have shown and described the particular form of dash potarrangement for exerting a resistance to the opening movement of thesuction-controlled throttle valve, I wish it to be clearly understoodthat I do not wish to limit myself to any particular form as variousforms canbe used, such as air dash pots or analogous devicesforexertinga' resistance to the movement of the suction controlledvalve, without departing from the spirit of my invention.

In order to provide means for adjusting the position of the Venturi tubewithin the tubular member forming the main air passage, the periphery ofthe tube is provided with an annular groove which is intersected by anobliquely arranged groove as clearly shown in Fig. 7, into which isadapted to extend a screw 24 and it will be seen that by loosening saidscrew and oscillating said Venturi tube, the same can be adjusted up anddown within the tubular member in order to adjust the relative positionof said Venturi tube in respect to the main fuel nozzle.

In Fig. 2, I have shown the Venturi tube in its intermediate positionwith the screw 24 within the annular groove and in order to adjust thesame either up or down, it is only necessary to turn the Venturi tubeuntil the screw is brought into register with the oblique slot and byoscillating the same and exerting a downward pressure or pullingupwardly on the tube, the same can be adjusted quickly in respect to thenozzle and locked in such position by tightening theset screw 24. a

From the foregoing description, it will be seen that I have provided acarbureter with a fuel chamber having a centrally arranged air passageformed by a tubular member arranged therein, which is provided with anair duct at its lower end, and with a valve-controlled fuel nozzlehaving passages communicating with the fuel chamber for supplying fuelto the nozzle directly from the fuel chamber. By this construction,means is provided for admitting air around the main fuel nozzle in orderto suck the fuel therefrom, which is conveyed by a Venturi tube to amixing chamber arranged above the auxiliary air chamber which has anopening communicating therewith for admitting an additional supply ofair, said auxiliary air chamber having a high speed nozzle extendingfrom the fuel chamber, and a suctioncontrolled floating valve mountedabove the end of the nozzle and adapted to be opened by the suction ofthe engine when the speed of the same is 1ncreased in order to increasethe richness of the mixture, means'being provided for re tarding theupward movement ,of the suction-controlled valve and for adjustnig therelative position of said retarding means in respect to said valve inorder to allow an initial free movement of the floating valve. I

The operation of my improved carbureter is as follows:

Supposing that the valves of the carbureter are in the position shown inFig. 2, when the throttle valve is opened, a partial vacuum is createdwithin the mixing chamher and Venturi tube so as to cause the fuel to besucked out of the main nozzle 14 and as the speed of the engineincreases, the vacuum is increased within the mixing chamber causing thefloating valve 33 to be raised and as this valve is allowed an initialfree movement, the same is raised until it is brought into engagementwith the depending ends of the fork and as the speed of the engine isincreased, the incoming air through the auxiliary air inlets 27 raisesthe valve against the retarding means so as to suck an additional chargeof fuel out of the high speed nozzle 30.

It will be seen that the upper end of the high speed nozzle is in aplane slightly below the plane of the lower edge of the floating valveso that liquid fuel is not drawn out of the high speed jet until thefloating valve has been raised to a considerable extent, caused by theincreased speed of the engine to which the upper end of the casing 35 isadapted to be connected, in the ordinary manner.

I claim:

1. In a carbureter, the combination with a centrally disposed Venturitube having a nozzle arranged therein, of a noncommunicating auxiliaryair chamber surrounding said Venturi tube provided with air inlets, amixing chamber arranged above said auxiliary air chamber havingcommunication with said Venturi tube and auxiliary air chamber, afloating suction controlled valve for controlling communication betweensaid auxiliary air chamber and mixing chamber, a nozzle arranged undersaid valve adjacent thereto, a pivoted member arranged in the path oftravel of said suction-controlled valve for retarding'the movementthereof, and means for holding said member out of contact with saidvalve to allow an initial movement of said floating suction controlledvalve. I

2. In a carbureter,-the combination with a shell having a liquid fuelchamber and a centrally disposed Venturi tube, of an auxiliary airchamber surrounding said Venturi tube provided with air inlets, a nozzlearranged within said Venturi tube, a nozzle arranged within saidauxiliary air chamber, a floating suction controlled valve arranged oversaid air chamber, a pivoted fork arranged in the path of travel of saidvalve and normally held out of contact therewith, and means forretarding the oscillation of said.- fork.

3. A carbureter having a Venturi tube, a nozzle arranged therein, anoncommunicating air chamber surrounding said Venturi tube provided withair inlets, a mixing chamber having communication with said Venturi tubeand auxiliary air chamber, ahigh speed nozzle arranged within said airchamber, and a floating valve slidably mounted upon said Venturi tube ata point adjacent the discharge end of said high speed nozzle for closingthe communication between said auxiliary air chamber and said mixingchamber.

at. A carbureter having a mixing chamber, and a main fuel nozzle and ahigh speed fuel nozzle for supplying liquid fuel thereto, a Venturi tubesurrounding the main fuel nozzle, an air chamber surrounding saidVenturi tube in which the high speed nozzle is disposed, a floatingvalve arranged over the auxiliary fuel nozzle for closing communicationbetween the auxiliary air chamber and said mixing chamber, and means forallowing an initial free movement of said floating valve and forretarding the final movement thereof.

5. In a carbureter, the combination with an air chamber having. airinlets, of a Venturi tube disposed centrally within said air chamber, afuel nozzle arranged within said air chamber, a fuel nozzle arrangedwithin said Venturi tube, a suction-controlled valve arranged over thefirst mentioned fuel nozzle, a movable member arranged in the path oftravel of said suction-controlled valve, and means for allowing aninitial free movement of said suction-controlled valve and for retardingthe final movement of said valve.

6. In a carbureter, the combination with a mixing chamber, of an airchamber having an opening communicating therewith, a Venturi tubeextending centrally through said air chamber, a main fuel nozzlearranged within said Venturi tube, a high speed nozzle arranged withinsaid air chamber, a suction-controlled floating valve for closing theopening communicating with the mixing chamber, a shaft mounted in saidmixingchamber, a member carried by said shaft arranged in the path oftravel of said suction-controlled floating valve, and normally out ofcontact therewith an arm fixed on said shaft, and a weight adjustablvmounted upon said arm for retarding the oscillation of said shaft.

7. A carbureter having a centrally disposed Venturi tube communicatingwith the mixing chamber, an auxiliary air chamber surrounding saidVenturi tube having a communication with said mixing chamber, and highspeed fuel nozzles arranged respectively within said Venturi tube andauxiliary air chamber, a suction-controlled floating valve for closingsaid auxiliary air chamber, a movable member arranged in the path oftravel of said floating valve and normally held out of contact therewithfor allowing the initial movement thereof, and means for adjusting therelative position of said member in respect to said valve.

8. In a carbureter, the combination with an auxiliary air chamber havingair inlets, of a fuel nozzle arranged in said air chamber, asuctiomcon'trolled valve for closing said chamber, a shaft, a membercarried by said shaft arranged in the path of travel of saidsuction-controlled valve, an arm carried by said shaft, and an adjustingscrew mounted in said arm for limiting the movement of said shaft in onedirection. i

9. In a carbureter, the combination with a suction-controlled floatingvalve, of a movable member arranged in the path of travel of said valve,a shaft upon which said movable member is mounted, means for retardingthe oscillation of said shaft, an arm carried by said shaft, and anadjusting screw mounted in said-arm for limiting the movement of saidshaft.

10. A carbureter having a Venturi tube provided with a fuel nozzle, andan auxiliary air chamber provided with a high speed fuel nozzle, amixing chamber disposed above said air chamber, a suction-controlledvalve for controlling communication between said auxiliary air chamberand said mixing chamber, and means for controlling saidsuction-controlled valve for allowing an initial free movement thereofand for retarding the final movement thereof.

11. A carbureter, formed of superposed castings, comprising a basecasting forming a fuel chamber, an intermediate casting, an auxiliaryair chamber and a top casting a mixing chamber, saidmixing chamber beingWin in communication with the air chamber, said fuel chamber having acentrally arranged air passage, a fuel nozzle arranged within saidcentrally arranged air passage, a Venturi tube arranged within saidpassage extending through saidair chamber into said mixing chamber, ahigh speed nozzle arranged within said auxiliary air chamber, asuction-controlled valve slidably mounted upon said Venturi tube forclosing the opening between said mixing chamber and air chamber, andmeans for retarding the upward movement of said suction-controlledvalve.

12. In a carbureter, the combination with a mixing chamber thereof, of aVenturi tube extending into said mixing chamber having a main fuelnozzle, an auxiliary air chamber surrounding said Venturi tube, a highspeed nozzle arranged within said auxiliary air chamber, asuction-controlled valve for closing said air chamber, a pivoted memberarranged in the path of travel of said suction? controlled-valve andnormally held out of contact therewith for allowing an initial freemovement of said valve, and means for retarding the movement of saidpivoted member when engaged by said valve.

13. In a carbureter, the combination with a fuel chamber, of anauxiliary-air chamber arranged above said fuel chamber, amixing chamberarranged above said auxiliary air chamber, a Venturi tube disposedcentrally Within said fuel chamber extending through sage of the highspeed nozzle,

said air chamber into said mixing chamber, a main fuel nozzle disposedwithin said Venturi tube, a floating suction controlled valve forclosing communication between said mlxing chamber and auxiliary airchamber, a fuel nozzle arranged within said auxiliary air chamber undersaid suction-controlled Valve, and means for allowing an initial freemovement of said valve and for retardin the final movement thereof.

14. In a carbureter, the combination with a main fuel nozzle, of aVenturi tube surrounding said nozzle, a main air inlet duct forsupplying air to said fuel nozzle, an auxiliary air chamber throughwhich said Venturi tube extends, a mixing chamber arranged above saidauxiliary air chamber, a floating suction-controlled valve mounted uponsaid Venturi tube for normally closing communication between saidauxiliary air chamber and mixing chamber, a high speed nozzle arrangedwithin said air chamber, and means for allowing said suction-controlledvalve an initial free movement and for retarding the final movementthereof.

15. In a carbureter, the combination with a fuel chamber, of a tubularmember arranged within said fuel chamber havin a flange for closing thesame and provided with an air inlet passage at its lower end, a

.fuel nozzle arranged within said tubular member, an auxiliary airchamber arranged above said fuel chamber, a mixing chamber arrangedabove said auxiliary air chamber, a Venturi tube mounted within saidtubular member extending through said air chamber and terminating in themixing chamber, a high speed nozzle arranged within said auxiliary airchamber, a floating suctioncontrolled valve mounted upon said Venturitube for closing the auxiliary air chamber, and means for retarding theupward movement of said floating valve.

16. In a carbureter, the combination with a main fuel nozzle, of a highspeed nozzle, air passages for supplying air to said nozzles, a mixingchamber adapted to receive fuel from said nozzles, a'floatingsuctioncontrolled air valve for closing the air pasan oscillating forkmember arranged in the path of travel of said suction-controlled valve,and normally held out of contact therewith, and

arranged in the path of travel of said suction-controlled valve forretarding the *upward movement thereof.

18. In a carbureter, the combination with an auxiliary air chamberhaving inlets, of a fuel nozzle'arranged within said air cham her; asuction-controlled valve for closing said air chamber, a pivoted forkarranged in the path of travel of said suction-controlled valve, a shaftupon which said fork is mounted, an arm carried by said shaft, and aweight adjustably mounted upon said arm.

19. A carbureter, havin a fuel chamber provided with a central airpassage, an air duct connected to the lower end of said pas' sage, afuel nozzle arranged within said passage, a Venturi tube arranged withinsaid passage above said fuel nozzle, an auxiliary air chamber arrangedabove said air passage through which said Venturi tube extends,a mixingchamber surrounding the upper end of said Venturi tube a floatingsuction-controlled valve slidably mounted upon said Venturi tube forclosing the auxiliary air chamber, a high speed nozzle arranged withinsaid auxiliary air passage, and means arranged in the path of travel ofsaid suction-controlled valve for retarding the upward movement thereof.

20. In a carbureter, the combination with a fuel chamber having acentral air passage, of an auxiliary air chamber arranged above saidfuel chamber, a Venturi tube arranged within said air passage extendingthrough said auxiliary air chamber, a mixing chamber arranged above saidauxiliary air chamber, a suction-controlled valve controllingcommunication between said mixing chamber and auxiliary air chamber, ahigh speed nozzle arranged within said .auxiliary air chamber, a fuelnozzle arranged within said Venturi tube, and means for retarding theupward movement of said suction-controlled valve.

21. In a carbureter, the combination with a high speed nozzle, of an airchamber in which said nozzle is mounted having air inlets, a mixingchamber arranged above said air chamber, a suction-controlled valve forcontrolling communication between said mixing chamber and air chamber, apivoted fork arranged in the path of travel of said suction-controlledvalve and-normally held out of contact therewith, and means for retardinthe movement of said fork,

22 carbureter having a main air passage and a Venturi tube arrangedtherein,

(lit) a nozzle arranged to deliver fuel thereto, a noncommunicating airchamber surrounding said Venturi tube, provided with an air inlet, amixin chamber having communication with said Venturi tube and auxiliaryair chamber, a high speed nozzle arranged within said air chamber, and afloating valve for controlling the communication between said auxiliaryair chamber and said mixing chamber.

28. A carbureter having an auxiliary air chamber provided with a highspeed nozzle, a suction controlled-valve for closing said auxiliary airchamber, said high speed nozzle being arranged adjacent the edge of saidvalve, a shaft, a fork fixed on said shaft arranged in the path oftravel of said suction controlled-valve, means carried by said shaft forlimiting the oscillation of said shaft for adjusting the relativeposition of said fork to said valve and means for retardin theoscillation of said shaft.

24. n a carbureter, the combination with a main fuel nozzle, of a highspeed nozzle, a suction-controlled valve arranged above said high speednozzle and adjacent to the discharge end thereof, a shaft, a member carried by said shaft arranged in the path of travel of saidsuction-controlled valve, means for retarding the oscillation of saidshaft, and means for adjusting the relative position of said member inrespect to said suction-controlled valve.

25. A carbureter, having a main air inlet passage provided with a fuelnozzle, an air chamber surrounding said passage, a mixing chamber havingcommunication with said air chamber and passage, a suction-controlledvalve for controlling communication between said mixing chamber and airchamber, a pivoted member arranged in the path of travel of saidsuction-controlled valve and normally held out of contact therewith, andmeans for retarding the movement of said pivoted member.

26. A carbureter, formed of superposed castings, the lower castingforming a fuel chamber, the intermediate casting an air chamber, and thetop casting a mixing chamber, said mixing chamber being in communicationwith the air chamber, said fuel chamber having a centrally arranged airpassage, a fuel nozzle arranged within said passage extending throughsaid air chamber into said mixing chamber, a suction-controlled valveslidably mounted upon said Venturi tube for closing communicationbetween said mixing chamber and air chamber, a high speed nozzlearranged within said air ciamber, and means for retarding the upwardmovement of said suction-controlled valve.

27. A carbureter having a mixing chamber and a passage for supplying airthereto, a fuel nozzle for delivering fuel into said passage, anoncommunicating auxiliary chamber surrounding said passage,communication with said mixing chamber, a high speed nozzle arranged insaid auxiliary air chamber, and a floating suction-controlled valve forcontrolling the communication between said auxiliary air chamber andmixing chamber.

meaiae pivoted member arranged in the path of travel of saidsuction-controlled valve,- means for adjusting the relative position ofsaid pivoted member in respect to said suction-controlled valve, andmeans for retarding the upward movement of said pivoted member.

29. In a carbureter, the combination with a main air inlet passagehaving a fuel nozzle, of a mixing chamber, a Venturi tube surroundingsaid nozzle for conveyin the partially mixed gases to themixing 0 amber,an auxiliary air chamber having an opening communicating with saidmixing chamber and provided with oppositely disposed air inlets, a highspeed nozzle arranged within said auxiliary air chamber,

a suction-controlled valve arranged adjacent said high speed nozzle forclosing the opening of said auxiliary air chamber, and a pivoted memberarranged in the path of travel of said suction-controlled valve forretarding the 11 Ward movementnthereof.

30. lln a car ureter, the combination with an auxiliary air chamber, ofa fuel nozzle arranged in said air chamber, a suction controlled valvefor closing said chamber, a shaft, a member carried by said shaftarranged in the pathof travel of said. suction controlled valve, an armcarried by said shaft, a weight adjustably mounted on said arm forretarding the oscillation of" said shaft and means carried by said shaftfor limiting the movement of said shaft in one direction.

31. A carburetencomprising a fuel chamher having a centrally arrangedair passage, a fuel nozzle disposed centrally Within said air passage, aVenturi tube slidably mounted within said air passage having an annulargroove intersected by an obliquely arranged groove, and a screwarranged'in the Wall of the air passage extending-intosaid groove forlocking said Venturi tube in adjusted position.

32. The combination with a suction controlled floating valve, of amovable member arranged in thepath of travel of said valve and normallyheld out of contact therewith, a shaft upon which said member is mountedmeans for retarding the oscillation of said shaft, and means carried bysaid shaft for limiting the movement thereof in one direction. 1 a

In testimony whereof I hereunto aflix my signature 'in the presence oftwo witnesses.

BURT NEUL'ON PIERCE.

Witnesses:

J. R. FRANCIS, J. E. Grimes;

